Thermal Conductivity of Ionic Liquids: Recent Challenges Facing Theory and Experiment

Journal of Solution Chemistry - Recently ionic liquids have been considered as prospective substances for application as heat transfer fluids, which requires accurate knowledge of their thermal...     

Mechanism of Passive Layer Formation during Electrochemical Oxidation of Copper(I) Sulfide

Russian Journal of Electrochemistry - The structure and phase composition of synthesized copper(I) sulfide are studied. It is shown that, both chalcocite (Cu2S) and jarleite (Cu31S16) phases can...     

Cold crystallization kinetics of slag from the joint smelting of oxidized nickel and sulfide copper ores

Journal of Thermal Analysis and Calorimetry - The cold crystallization kinetics of the glass-crystal composition (90.3 vol% of glass) made of slag from the joint smelting of oxidized nickel and...     

First results of investigation of radiation from positrons in a crystalline undulator

Radiation emitted by positrons moving in a periodically deformed crystal has been experimentally observed for the first time. Radiation spectra have been measured in a wide energy range. Experimental evidence has been obtained for an undulator peak in a radiation spectrum, which is qualitatively consistent with calculations. Crystalline undulators ensure an equivalent magnetic field of 1000 T and a period in the submillimeter range and can therefore be used to generate x-ray and gamma radiation that is a hundred times harder than radiation in usual undulators.     

Physical principles of forecasting the characteristics of the ELF environmental electromagnetic background noise from the meteorological factors

Physical principles of forecasting the environmental electromagnetic background noise (EMBN) characteristics in the extra low frequency (ELF) range are suggested in the work based on an analysis of the meteorological conditions. Dependences of the spectral EMBN characteristics in the ELF range on the meteorological parameters such as the atmospheric pressure, ground wind velocity, temperature, and relative air humidity are obtained. Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 9, pp. 89–94, September, 2008.     

Study of the Involvement of <Superscript>8</Superscript>Be and <Superscript>9</Superscript>B Nuclei in the Dissociation of Relativistic <Superscript>10</Superscript>C, <Superscript>10</Superscript>B,and <Superscript>12</Superscript>C Nuclei

The results obtained by estimating the contribution of 8Be and 9B nuclei to the coherent dissociation of ¹⁰C, ¹⁰B, and ¹²C relativistic nuclei in nuclear track emulsions (“white” stars) are presented. The selection of white stars accompanied by 9B leads to a distinct peak appearing in the distribution of the excitation energy of 2α2p ensembles and having a maximum at 4.1 ± 0.3 MeV. A 8Be nucleus manifests itself in the coherent-dissociation reaction ¹⁰B → ²He + H with a probability of (25 ± 5)%, (14 ± 3)% of it being due to 9B decays. The ratio of the branching fractions of the ⁹B + n and ⁹Be + p mirror channels is estimated at 6 ± 1. An analysis of the relativistic dissociation of ¹²C nuclei in a nuclear track emulsion revealed nine 3α events corresponding to the Hoyle state.     

A two-jet plasmatron for the spectrochemical analysis of geological samples

The analytical possibilities with a two-jet plasmatron with non-consumable electrodes have been investigated. Large amounts of easily ionised additives present in the plasma enhance atom line intensities of trace elements, the effect being greater the lower the ionisation potential of the element but the effect on ion line intensities is not significant. The temperature of the plasma is only slightly affected by the ionisation potential of the substance introduced into the plasma.Analytical errors caused by variations in the matrix and mineralogical composition of samples are of the same order as the random error of analysis. The analysis of different types of rock samples can be made using a single standard procedure giving a relative standard deviation of 4–6 % and detection limits between 10^?5 and 10^?7 %. A feature of the analytical method is the direct analysis of solid samples.     

Wide-aperture tomography of emissive objects

Classical tomohraphic methods for image reconstruction are constructed based on the assumption that projection data were obtained by integration over infinitely thin lines. However, a detector receiving a signal in a real experiment always has a certain width and, in a more general case, a nonzero angular aperture specified by a collimator. A modified iterative algorithm on the basis of the Neumann technique is proposed that makes it possible to take the actual system of signal recording in the process of reconstruction into account. The computational experiment is carried out on a model simulating local two-dimensional distributions of emission coefficients. Modification of the algorithm consists in the utilization of nonlinear relaxation and regularizing cubic splines. This makes it possible to stabilize the iteration process and to avoid a loss in accuracy when the noise level in projection data increases. The algorithm is also stable to certain parameters variations of the geometry of collection of projection data. The results of reconstruction by using the method proposed here are compared with the results of operation of the classical method of tomography—the method of inverse projection with filtering (Shepp-Logan filter).